code: def test_is_requirements_file():
      assert _is_requirements_file("-r req.txt")
      assert _is_requirements_file("-r  req.txt")
      assert _is_requirements_file("--requirement req.txt")
      assert _is_requirements_file("--requirement  req.txt")
      assert not _is_requirements_file("req")
  
imports: import importlib
  import os
  import sys
  from unittest import mock
  import importlib_metadata
  import pytest
  import mlflow
  import mlflow.utils.requirements_utils
  from mlflow.utils.environment import infer_pip_requirements
  from mlflow.utils.requirements_utils import _capture_imported_modules, _get_installed_version, _get_pinned_requirement, _infer_requirements, _is_comment, _is_empty, _is_requirements_file, _join_continued_lines, _normalize_package_name, _parse_requirements, _prune_packages, _PyPIPackageIndex, _strip_inline_comment, _strip_local_version_label
label_desc: Use image node_id 3 for calling a global function with example usage: test_is_requirements_file() without return types